Fun build that I've used recently to PvP, GLS can still be useful without even landing since people tend to roll into you to attack when used, with the 45 dex cast speed you will have time to get a parry in with the parrying dagger. If you want to go try hard you can attune SLB. Alternatively you can equip pyro flame in left hand and attune something like GC to mixup castings, this can be effective but tends to get a bit fiddly.
